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Nov. 23, 2009 - A still experimental erectile dysfunction drug -- avanafil -- promises erections in just 30 minutes or less, according to study results announced by the drug's manufacturer.

The phase 3 study, not yet published in a peer-reviewed scientific journal, included 646 men with erectile dysfunction (ED). At the highest dose tested (200 milligrams), nearly 80% of sexual attempts resulted in erections good enough for intercourse.

Study investigator LeRoy Jones, MD, associate professor of urology at the University of Texas Health Science Center, said the new drug will offer a new alternative to men seeking "an improved experience" with current erectile dysfunction drugs.

"These data suggesting that avanafil achieves a full effect in 30 minutes or less, with a window of opportunity extending beyond six hours, would be a welcome option for ED treatment," Jones said in a news release from Vivus Inc., which has licensed the drug from Mitsubishi Tanabe Pharma Corp.

In the study, men received either an inactive placebo or avanafil at a dose of 50 milligrams, 100 milligrams, or 200 milligrams. Successful intercourse was reported by:

27% of men taking placebo (up from 13% at the start of the study)

41% of men taking avanafil 50 milligrams (up from 13% at the start of the study)

57% of men taking avanafil 100 milligrams (up from 14% at the start of the study)

57% of men taking avanafil 200 milligrams (up from 12% at the start of the study)

Avanafil's most frequent side effect was headache, reported by 7% of men receiving the drug and by 1.2% of men taking placebo. Other common side effects included flushing (4.6% of men on avanafil vs. none on placebo) and nasal congestion (2.3% of men on avanafil vs. 1.2% on placebo).

Avanafil works the same way as the three other ED drugs currently on the market: Viagra, Cialis, and Levitra. All these drugs target an enzyme called PDE5; avanafil appears to inhibit this enzyme more selectively than the other.

A Vivus news release suggests that in addition to working faster than Viagra, Cialis, and Levitra, the new drug may have fewer side effects.

The current study, dubbed REVIVE, is the first of four phase 3 trials of avanafil. Two of the other studies will look at how well the drug helps erectile dysfunction in men with diabetes and in men who have had prostate surgery. A third study, enrolling 600 men at 40 U.S. medical centers, began in March 2009 and will continue for one year.

Vivus expects to submit avanafil for FDA approval in late 2010 or early 2011.